Just spotted this interesting article in DM regarding google cast products, don't have this issue myself as not using either of these - did have an early chrome cast but gave up with it some while ago it was only music though. Perhaps this is why I had probs.
Not sure if it will get blocked so you can also see it by searching for
"Google Cast flaw causes Wi-fi connections crash"
"The bug is thought to affect Google Home and Chromecast users who have a number of popular routers, although the problem may extend to other Android devices that feature the Cast facility."
Apparently it was discovered by TP-Link employee in China !!!